HydroBody Class Reference

#include <HydroBody.h>

Public Member Functions
	HydroBody (ISimObjectCreator *creator, const std::string &angularRateName, double convergenceTime, rigid_body::MunkMoment munk)
void	SetInertia (const double rigid[6], const double added[6])
const BodyKinematics6Dof &	Kinematics () const
	The kinematic states and their indices.
const double *	RigidInertia () const
	The diagonal of the rigid-body inertia.
const double *	AddedMass () const
	The diagonal of the added mass.
double	InverseMass (int i) const
	The entry i of the diagonal of M^-1.
hydro_body::FlowFrame	Frame (const double *X, const double waterVel_n[3]) const
hydro_body::FlowFrame	Frame (const environment::wake::BodyFlowInteraction &flow, double t, const double *X) const
	Frame(X, waterVel_n) with the water velocity of flow at the body origin at time t (BodyFlowInteraction::WaterVelocity).
hydro_body::FlowFrame	LocalFrame (const double *localX, const double waterVel_n[3]) const
hydro_body::FlowFrame	LocalFrame (const environment::wake::BodyFlowInteraction &flow, double t, const double *localX) const
	LocalFrame(localX, waterVel_n) with the water velocity of flow at the body origin at time t.
void	Derivatives (const hydro_body::FlowFrame &frame, const hydro_body::Wrench &wrench, const double *X, double *XDot) const
void	AddJacobian (const double *localX, const hydro_body::FlowFrame &frame, double dWrench[6][6], double *J, int nStates) const

Detailed Description

The states, the inertia and the derivatives of a rigid body moving through water. See HydroBody.h.

The inertia is diagonal: M = diag(M_RB) + diag(M_A), with M_RB the rigid body's and M_A the added mass, entries 0-2 translational and 3-5 rotational about the body axes.

Constructor & Destructor Documentation

HydroBody()

HydroBody::HydroBody	(	ISimObjectCreator *	creator,
		const std::string &	angularRateName,
		double	convergenceTime,
		rigid_body::MunkMoment	munk
	)

Registers the kinematic states with creator (BodyKinematics6Dof). The inertia is zero until SetInertia() is called.

Parameters

creator	The creator of the SimObject that owns the body.
angularRateName	The name of the angular-rate state, for example AngVel or Omega.
convergenceTime	The time constant [s] with which the quaternion norm is driven towards one.
munk	Whether the moment carries the Munk moment (rigid_body::MunkMoment).

Member Function Documentation

AddJacobian()

void HydroBody::AddJacobian	(	const double *	localX,
		const hydro_body::FlowFrame &	frame,
		double	dWrench[6][6],
		double *	J,
		int	nStates
	)		const

Adds the kinematic blocks to a Jacobian and writes its velocity block: M^-1 (dWrench + the derivative of the Coriolis-centripetal terms), the water velocity held fixed (rigid_body::AddOmegaTermsJacobian).

Parameters

[in]	localX	The object's slice of the state vector, as OdeJacobian is handed it.
[in]	frame	The frame of localX (LocalFrame()).
[in,out]	dWrench	The derivative of the body's wrench against (u, v, w, p, q, r); the Coriolis-centripetal terms are added to it.
[in,out]	J	The object's Jacobian, nStates by nStates, row major; the velocity block is overwritten, the kinematic blocks are added to.
[in]	nStates	The number of states of the object.

Derivatives()

void HydroBody::Derivatives	(	const hydro_body::FlowFrame &	frame,
		const hydro_body::Wrench &	wrench,
		const double *	X,
		double *	XDot
	)		const

The derivatives of the 13 kinematic states: the kinematics and M^-1 (wrench + the Coriolis-centripetal terms).

Parameters

[in]	frame	The frame of X.
[in]	wrench	The sum of the body's loads at X.
[in]	X	The global state vector.
[out]	XDot	The global derivative vector; only the 13 kinematic entries are written.

Frame()

hydro_body::FlowFrame HydroBody::Frame	(	const double *	X,
		const double	waterVel_n[3]
	)		const

The flow frame of the global state X (as OdeFcn is handed it), with the given water velocity.

Parameters

[in]	X	The global state vector.
[in]	waterVel_n	The water velocity at the body origin, NED [m/s].

LocalFrame()

hydro_body::FlowFrame HydroBody::LocalFrame	(	const double *	localX,
		const double	waterVel_n[3]
	)		const

The flow frame of the object's state slice localX (as OdeJacobian is handed it), with the given water velocity.

SetInertia()

void HydroBody::SetInertia	(	const double	rigid[6],
		const double	added[6]
	)

Sets the inertia and inverts it.

Parameters

rigid	The diagonal of the rigid-body inertia M_RB.
added	The diagonal of the added mass M_A.

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The documentation for this class was generated from the following file:

• webfhsim/reloadrepos/fhsim_base/src/body/HydroBody.h